The US ambassador to Britain, Matthew Barzun, has rejected an opportunity to criticise the Guardian newspaper for publishing leaks from the former National Security Agency employee Edward Snowden, saying he wanted to focus on the importance of the debate about the trade-offs between security and privacy.

Barzun was appearing on the BBC's Andrew Marr Show for the first time since his arrival in London in June, and talked about the impact of the debate on national security created by Snowden's leaks. He also stressed that President Barack Obama was clear that his response to the leaks should not have "a chilling effect on the press".

Asked if he shared the UK security services' concerns about the threat to national security from the leaks, he said he wanted to focus on the "importance of having this debate about what the trade-offs are between security and privacy, between transparency and secrecy, and to do so in a way that protects whistleblowers – which is different, by the way, from wholesale releasing of information, hundreds of thousands of documents".

Barzun said Obama had "promised to seek to balance the legitimate security concerns of not only our citizens but of our allies, and balance those with the privacy concerns shared by all people". He said the president "put in specific measures to protect whistleblowers if they see something illegal or unethical. That's an important part of the balance".